Sql 如何使用多种条件更新表

我需要用多个条件更新表中的多个列

例如，这是我的查询

update Table1 
set weight= d.weight,
    stateweight=d.stateweight,
    overallweight=d.overallweight 
from
     (select * from table2)d 
      where table1.state=d.state and
          table1.month=d.month and 
          table1.year=d.year

如果表匹配所有三列（州、月、年），则应仅更新权重列；如果表匹配（州、年），则应仅更新stateweight列；如果表匹配（年），则应仅更新overallweight列

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注意：我不能单独为每个条件编写更新查询，因为它是一个巨大的表，请帮助我们

好的，这里是另一个，可能是您需要的：

update Table1 
set weight = case when table1.state = d.state and
                       table1.month = d.month and 
                       table1.year = d.year
                  then d.weight
                  else weight end,
     stateweight =  case when table1.state = d.state and
                              table1.month <> d.month and 
                              table1.year = d.year
                  then d.stateweight 
                  else stateweight end,
    overallweight = case when table1.state <> d.state and
                              table1.month <> d.month and 
                              table1.year = d.year
                  then d.overallweight 
                  else overallweight end
from
     (select * from table2)d 
      where
          table1.year=d.year

年和月列在这里是分隔的，因为它们是保留字

使用核心SQL-2003之外的以下功能： T641，“多列分配”

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它可以工作

哪个数据库管理系统？（发布的查询不是ANSI SQL。）嗨，tks for replay，上面的查询只满足一个条件，那么其他两个条件呢（如果它匹配（state，year），它应该只更新stateweight列，如果它匹配（year），它应该只更新overallweight列）对不起，显然我读得不够仔细。。。稍后再看。

update Table1 
set (weight,
     stateweight,
     overallweight) = 
     (select * from table2 d 
      where table1.state = d.state and
            table1."month" = d."month" and 
            table1."year" = d."year")

with
cte as  (   select      t1.Year,
                        t1.Month,
                        t1.State,
                        Weight      =   MAX(case
                                                when t1.State = t2.State and t1.Month = t2.Month
                                                then t2.Weight
                                                else t1.Weight
                                            end),
                        StateWeight =   MAX(case
                                            when t1.State = t2.State and t1.Month = t2.Month
                                            then t2.StateWeight
                                            else t1.StateWeight
                                        end),
                        Overweight  =   MAX(t2.Overweight)
            from        Table1  as  t1
            inner join  Table2  as  t2  on  t1.Year = t2.Year
            group by    t1.Year, t1.Month, t1.State)
update      t1
set         Weight  =   tv.Weight,
            StateWeight =   tv.StateWeight,
            Overweight = tv.Overweight
from        Table1  as  t1
inner join  cte     as  tv  on  t1.Year = tv.Year
                            and t1.Month = tv.Month
                            and t1.State = tv.State;